Origen

Sex entered the language in medieval times from Latin sexus, and first referred to the two genders. Women have been the fair or the fairer sex since the middle of the 17th century, when men were sometimes called the better or the sterner sex. In reference to hanky-panky, sex has only been used since the early part of the 20th century, with D. H. Lawrence being among the first to talk of ‘having sex’. To sex up has been around as an expression since the 1940s, meaning ‘to make more sexy’. A new use hit the headlines in 2003 when a BBC journalist claimed that the British Labour government had knowingly ‘sexed up’ a report on whether Iraq possessed weapons of mass destruction. People or things have been sexy in the literal sense since the 1920s. The sense ‘very exciting or appealing’ appeared in the 1950s, and has led to some odd phrases, like this from the New York Magazine in 2003: ‘Sexy flat-panel screen, woofer, and remote control included’.